HEIDENHAIN TNC 620 User Manual page 303

The TNC 620 uses an extended interface for communication
between the PLC and NC. This is a new, symbolic Application
Programmer Interface (API). The familiar previous PLC-NC interface
is also available and can be used if desired. The machine tool
builder decides whether the new or old TNC API is used. Enter
the name of the symbolic operand as string to wait for the defined
condition of the symbolic operand.
The following conditions are permitted in the FN 20 block:
Condition Abbreviation
Equal to ==
Less than <
Greater than >
Less than or equal <=
Greater than or >=
equal
In addition, the FN20: WAIT FOR SYNC function is available. WAIT
FOR SYNC is used whenever you read, for example, system data
via FN18 that require synchronization with real time. The TNC stops
the look-ahead calculation and executes the subsequent NC block
only when the NC program has actually reached that block.
Example: Stop program run until the PLC sets marker 4095 to 1
32 FN 20: WAIT FOR M4095==1
Example: Stop program run until the PLC sets the symbolic
operand to 1
32 FN 20: APISPIN[0].NN_SPICONTROLINPOS==1
Example: Pause internal look-ahead calculation, read current
position in the X axis
32 FN 20: WAIT FOR SYNC
33 FN 18: SYSREAD Q1 = ID270 NR1 IDX1
TNC 620 | User's Manual
HEIDENHAIN Conversational Programming | 3/2014
Additional functions
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